Ultrahigh-Temperature Ceramic-Polymer-Derived SiOC Ceramic Composites for High-Performance Electromagnetic...

High-performance electromagnetic interference (EMI) shielding materials for a high-temperature harsh environment are highly required for electronics and aerospace applications. Here, a composite made of ultrahigh-temperature ceramic- and polymer-derived SiOC ceramic (PDC-SiOC) with high EMI shielding was reported for such applications. A total EMI shielding efficiency (SE_T) of 26.67 dB with a thickness of 0.6 mm at the Ka-band (26.5-40 GHz) was reported for ZrB₂ fabricated by spark plasma sintering, which showed reflection-dominant shielding. A unique interface of t-ZrO₂ was formed after the introduction of PDC-SiOC into ZrB₂. This interface has better electrical conductivity than SiOC. The composites also displayed reflection-dominant shielding. Accordingly, the composite with a normalized ZrB₂ fraction of 50% pyrolyzed at 1000 °C exhibited a significant SE_T of 72 dB (over 99.99999% shielded) with a thickness of 3 mm at the entire Ka-band. A maximum SE_T of 90.8 dB (over 99.9999999% shielded) was achieved with a thickness of 3 mm at around 39.7 GHz.